Ni/La2O3 catalysts prepared by different synthesis routes were applied in the Oxidative Reforming of CH4 in the presence of CO2 and O2 (Oxy-CO2). The perovskite-type oxide LaNiO3 (NLP) and the NiO/La2O3 catalytic precursors were synthesized respectively by the citrate and wet-impregnation methods, being the latter calcined at 773 K (NL5) and 1073 K (NL8). The synthesized precursors, the fresh and the spent catalysts were characterized by TG-DTA, XRF, XRD, TPR-H2, TPSR, TPO, BET, BJH and HRTEM. The NLP sample, which presented the smallest average Ni crystal size, also showed higher CH4 conversion (circa 85 %), quite similar to NL8 but 22 % higher than NL5. After 20 h of reaction, the NL8 catalyst presented a larger Ni particle size and consequently greater sintering than the other catalysts, but did not exhibit deactivation, suggesting structural stability. The results also indicated that NLP and NL8 samples, despite their different preparation methods, have similar structural and textural properties, as well as similar catalytic performances. This suggests that, with the impregnation method, it is possible to obtain materials with catalytic performance comparable to those prepared using perovskite precursors.

A new method for synthesis of catalysts with core@shell architecture has been developed for syngas production via dry reforming of methane (DRM). This route is based on the confinement of St & ouml;ber particles (silica nanospheres) by nickel phyllosilicates and a layer-analogous decoration made of SiO2 (shell). Dry reforming catalysts based on non-noble metals suffer from deactivation via sintering and coke formation. Core@shell structures offer a strategy to enhance stability and control metal dispersion. In this work, the St & ouml;ber particles were obtained and then nickel phyllosilicate was synthetized over them (NiPS); silica was deposited on the resulting material producing a decorated material (S0@NiPS) and the effect of its aging under hydrolysis conditions for 12, 24, 36 and 48 h was evaluated (S12, S24, S36 and S48@NiPS). It was possible to demonstrate the efficiency of the proposed structures, with reagent conversion above 90 %, good yield to syngas and no signs of deactivation in the catalytic test at 700 degrees C (coking condition), for the S24@NiPS sample (reducible nickel content 8 % w/w). The superior activity of S24@NiPS is attributed to optimal Ni dispersion and shell structure, balancing accessibility and confinement. The order of activity obtained was: S24@NiPS > S12@NiPS > NiPS > S36@NiPS > S48@NiPS > S0@NiPS. The materials were characterized by XRD, TPR-H2, TPO-O2, TEM, EDS and TPSR-DRM. The modification of the hydrolysis time changed the properties of the catalysts: the shortest and longest times generated the less active catalysts. These findings offer a route to a coke-resistant catalysts for CO2 valorization and methane upgrading.

In this work, heterostructured photocatalysts were prepared with TiO2-P25 nanocrystals dispersed on two-dimensional layers of g-C3N4. Different g-C3N4:TiO2 ratios (25 %, 50 % and 75 %) were prepared using a wet method under ultrasonic exfoliation and thermal treatment under an oxidizing atmosphere. The heterojunctions were confirmed by X-ray diffraction, and electron microscopy, showing TiO2 nanocrystals anchored onto the surface of the g-C3N4 structure. The obtained heterojunctions increased light absorption from the ultraviolet to the visible spectrum and reduced the recombination of photoinduced charge carriers confirmed by photoluminescence and band gap energy (Eg) measurements. The photocatalytic performance was evaluated in the degradation of p-toluic acid (p-TA) (20 mg L-1) under UVA LED at 365 nm, a polychromatic lamp (UVA-UVB-visible) and solar radiation. The g-C3N4:TiO2 ratio of 25 % showed the best performance, reaching 95 % degradation after 180 min under solar radiation. The reuse tests showed that the mineralization capacity determined by total organic carbon (TOC) remained stable for 6 cycles, achieving 80.8 % TOC degradation. The heterojunction induced a significant alteration in the rheological behavior of the suspension, which made the g-C3N4-TiO2 easily recoverable, unlike the pure TiO2. The radical scavengers study indicated that the superoxide anion radical (O-2(center dot-)) is the main oxidative species in p-TA photodegradation on g-C3N4-TiO2 photocatalyst. The greatest advantage of the g-C3N4 in the composite was the absorption of light in the visible range and facile catalyst recovery for reuse while presenting photocatalytic activity similar to TiO2.

A large volume of highly acidic vegetable oils generated as waste could be utilized to produce low-cost biofuels without competing with food production. This study investigated the conversion of oleic acid (OA), used as a model fatty compound, in a micropyrolysis apparatus under conditions similar to those employed in fluidized catalytic cracking (FCC) of petroleum feedstocks. The influence of small-micropore size zeolites (ZSM-5) and large-micropore size zeolites (Y), in both their acidic H- and basic Na-forms, on the product distribution was evaluated. Oleic acid was pre-adsorbed onto the zeolites at a mass ratio Catalyst:OA = 10:1. Thermal cracking of pure oleic acid was limited, predominantly producing linear 1-alkenes and carboxylic acids. Conversion in the presence of catalysts was enhanced, resulting in the formation of a greater variety of hydrocarbons. Branched and cyclic alkanes, as well as polyaromatics hydrocarbons, were produced in greater quantities on Y zeolites compared to ZSM-5, due to the larger micropore diameter of the Y zeolite. Among the catalysts, Na-Y produced the highest number of hydrocarbons, predominantly within the gasoline range. These results are promising for the co-processing of fatty residues in the FCC, promoting the production of second-generation drop-in biofuels and bio-based chemicals, and contributing to industrial decarbonization.

NiMnAl oxides catalysts obtained from coprecipitated precursors were used in the PET glycolysis depolymerization reaction. These precursors exhibited different phases, including LDH, hausmannite, and rhodochrosite depending on the synthesis conditions. The NiMnAl trimetallic oxides displayed higher surface area and pore diameter than MnAl bimetallic oxide. Sodium-based precipitants formed a more crystalline manganese oxide phase and a higher synthesis yield than the ammonium carbonate/ hydroxide. Catalysts containing a lesser Ni/ Mn molar ratio exhibited higher activity for PET glycolysis. The presence of nickel in NiMnAl oxide improved from 49 % to 96 % the catalyst recovery after the reaction. This property relates to a strong electronic interaction between nickel and manganese and the suppressed Jahn-Teller distortion effect. The best catalyst was Ni0,22Mn0,45Al0,33-Sod, reaching 100 % PET conversion and 85 % BHET yield in the following conditions: 60 min, catalyst: PET = 0.5 %, EG: PET = 5:1. This catalyst demonstrated high performance after 5 cycles of reuse without calcination between cycles. Kinetic modeling revealed an initial shrinking core behavior changing to a pseudo-first-order model at the later stage of the reaction.

This work presents an evaluation of the industrial residue from exhausted black wattle bark after the extraction of tannin for use as a new feedstock for biofuel production, without competing with food production. The physicochemical and thermodynamic properties, the influence of temperature on pyrolysis products and multicomponent kinetics were evaluated. Principal component analysis showed that sugars, carboxylic acids, ethers/esters, furans and aldehydes were formed as primary products of pyrolysis at 450 degrees C. At 550 degrees C, phenols and mainly ketones were favored, especially acetone and 2,3-butanedione. Pyrolysis at 650 degrees C favored the production of aldehydes, alcohols, and 1-alkene, polyene and alkane hydrocarbons. After an upgrade, the series of 1-alkenes produced, with carbons C7 to C16, could be suitable for a range of gasoline and jet fuels. Kinetic modeling was based on the deconvolution of the mass loss of three events of the pseudo-components: hemicellulose (DE-HC), cellulose (DE-CL) and lignin (DE-LG). The activation energy for kinetic models Friedman, Flynn-Wall-Ozawa, Kissinger-Akahira-Sunose and Starink presented average values of -141.4-149.4 for DE-HC, -190.5-200.9 for DE-CL and -237.2-252.3 kJ mol-1 for DE-LG. This study encourages using agro-industrial waste to produce second-generation drop-in biofuels and bio-based chemicals, aiming at industrial decarbonization.

The pyrolysis of vegetable oil waste is an alternative way to convert biomass into high-quality second-generation biofuels, with social, economic and environmental sustainability. The present work deals with the pyrolysis of oleic acid as a model compound and an industrial vegetable oil residue on CuNiAl mixed oxide catalysts, derived from layered double hydroxides. Reactions of the oils pre-adsorbed on the catalysts (catalyst:oil mass ratio of 5:1) were performed at 550 °C on a micro-pyrolysis system and the analyses of volatile products were carried out online using GC/MS. Copper addition to NiAl catalysts increased the cracking of oleic acid. Increasing copper content also decreased the formation of aromatics and coke precursors, as well as oxygenated compounds. The CuNiAl catalyst with a Cu/Ni ratio of 0.4 showed strong catalytic activity in the conversion of an industrial vegetable oil residue with a high volume of free fatty acids produced. Compared to the non-catalytic reaction, the catalyst reduced the content of oxygenates and increased the content of hydrocarbons, particularly in the gasoline range (C5–C9). The CuNiAl oxide catalyst was able to convert vegetable oil residues into hydrocarbons in the range of gasoline, kerosene and diesel, and also linear alkylbenzenes as chemical precursors for surfactant production.

The chemical recycling of poly(ethylene terephthalate) (PET) residues was performed via glycolysis with ethylene glycol (EG) over Mg-Fe and Mg-Al oxide catalysts derived from layered double hydroxides. Catalysts prepared using the high supersaturation method (h.s.c.) presented a higher surface area and larger particles, but this represented less PET conversion than those prepared by the low supersaturation method (l.s.c.). This difference was attributed to the smaller mass transfer limitations inside the (l.s.c.) catalysts. An artificial neural network model well fitted the PET conversion and bis(2-hydroxyethyl) terephthalate (BHET) yield. The influence of Fe in place of Al resulted in a higher PET conversion of the Mg-Fe-h.s.c. catalyst (~95.8%) than of Mg-Al-h.s.c. (~63%). Mg-Fe catalysts could be reused four to five times with final conversions of up to 97% with reaction conditions of EG: PET = 5:1 and catalyst: PET = 0.5%. These results confirm the Mg-Fe oxides as a biocompatible novel catalyst for the chemical recycling of PET residues to obtain non-toxic BHET for further polymerization, and use in food and beverage packaging.

This work aimed to compare two different catalysts in the production of a long chain ketone, intermediate in the production of hydrocarbons, during pyrolysis of tetradecanoic acid as a model fatty acid. The studied variables were the temperature, 450 and 600 ºC, and catalysts, γ-Al2O3 and Nb2O5, the latter has never been studied under such conditions. Pyrolysis experiments were performed in a micro-pyrolyzer coupled to a gas chromatograph with mass spectrometry detector (GC-MS). In all pyrolysis conditions, 14-heptacosanone was formed in varied amounts. Under the best conditions, for pyrolysis at 600 ºC, using γ-Al2O3 as catalyst, the yield of 14-heptacosanone was 18% and the yield of hydrocarbons 24%. The major hydrocarbon product obtained was 1-dodecene. Among the partially deoxygenated compounds, the main products were the ketones 14-heptacosanone and 2-pentadecanone. The present experimental work confirmed also the possibility to obtain hydrocarbons having a chain length longer than the chain length of the original fatty acid reagent, due to a ketonization route followed by decarbonylation.

The present work deals with the production of hydrocarbons in the C5–C12 range obtained from the fast micropyrolysis of a laboratory-grown Desmodesmus sp. microalgae. It compares the properties of this specific fraction of hydrocarbons using or not using transition alumina catalysts during pyrolysis in experiments with both pure dried microalgae and its n-hexane extract. The microalgae were characterised using thermogravimetry (TG) and CHN analysis; the n-hexane extract was analysed through Fourier transform infrared spectroscopy (FTIR). The pyrolysis experiments were performed in a multi-shot pyrolyser connected online with a gas chromatograph coupled to a mass spectrometer (GC/MS). The composition of the C5–C12 fraction was compared to that of an industrial pyrolysis gasoline. The results of pyrolysis at 600 °C show that the alumina catalyst increases the quantity of C5–C12 hydrocarbon families when compared to purely thermal pyrolysis, representing about 40% of all the dry microalgae pyrolysis products. In the case of n-hexane extract, the C5–C12 area fraction corresponds to 33.5% of the whole products’ area when pyrolysis is conducted with an alumina catalyst. A detailed analysis shows that linear molecules, mainly unsaturated, are predominant in the products. Dry biomass formed more aromatic but less cyclic and alkylated molecules in relation to the n-hexane extract. Nitrogen products, essentially alkylated pyrroles, were produced in large quantities when dry biomass was used but were below the detection limit when pyrolysing the extracts. Thus, the extraction with hexane proved to be an effective way to remove nitrogen compounds, which are undesirable in fuels. The estimated low heating values of the present C5–C12 pyrolysis hydrocarbon fractions (between 43 and 44 MJ/kg) are quite comparable to the reported values for reformulated and conventional industrial gasolines (42 and 43 MJ/kg, respectively).

High acidic vegetable oil feedstocks and wastes are not suitable for conventional biodiesel production. These wastes could be used to produce cheap hydrocarbon-rich biofuels without affecting food production. In this work, we studied the hydrogen-free fast pyrolysis and deoxygenation of an acidic industrial vegetable oil waste for biofuels and chemicals production, assessing the effect of Ce or Zr on NiAl mixed oxides obtained from layered double hydroxides. Oily waste (OW) was pre-adsorbed on the catalysts using a Catalyst:OW mass ratio of 5:1. Without a catalyst, pyrolysis of OW, containing triglycerides and a high percentage of free fatty acids, produced mainly 1-alkenes, lower carbon chain fatty acids, and fatty acid esters. Catalytic pyrolysis increased hydrocarbons favoring 1-alkenes between propene and 1-heptadecene, as well as alkyl-benzenes. Linear alkylbenzenes are feedstock for the production of biodegradable surfactants. NiAlCe was most selective to polyenes, alkanes and ketones, while NiAl and NiAlZr catalysts were efficient in producing aromatics, alkenes and light hydrocarbons in the GLP and gasoline range (C3-C10). The combination of acidic and metallic properties on high surface area unsupported bulk mixed oxide catalysts can be used to maximize the production of specific-range hydrocarbons for second-generation drop-in biofuels and bio-based surfactant precursors, towards the decarbonization of industry.

Three different microalgae species, Desmodesmus sp., Nannochloropsis oculata and Halamphora coffeaeformis were grown under controlled conditions. The resulting dry biomass was characterized by TG-DTA (thermogravimetry-differential thermal analysis) and extracted with three solvents having different polarities. The extracts gross mass yields varied from 2% using n-hexane to 23% (or 74% when subtracting the volatiles and ashes) when using methanolchloroform whatever the microalgae species. Fourier transform infrared (FTIR) spectra of all extracts suggested the presence of fatty esters and acids. The extracts were pyrolyzed at 600 °C, using a micro pyrolizer coupled to a gas chromatograph-mass spectrometer (GC-MS), without and with γ-alumina as catalyst. Hydrocarbons concentrations varied respectively from 92% in the better case to 46% in the worst case. The C9-C15 fraction of these hydrocarbons, potentially useful for biokerosene formulation, was object of detailed analysis. In this fraction, nitrogenous products had concentrations always lower than 0.1%. The main hydrocarbons produced were linear 1-alkenes for thermal pyrolysis whereas for pyrolysis with γ-alumina, linear 1-alkenes and also alkenes isomers and linear alkanes, together with cyclic and aromatic compounds were observed for all microalgae species, but in different proportions. The C9-C15 fraction of pyrolyzed extracts can be considered as precursor for biokerosene or direct “drop in” fuel for kerosene petroleum fraction.

Residual lipids with high fatty acid content represent an important source of raw material for renewable biofuels. They are not suitable for the production of biodiesel via alkaline transesterification but can be converted to biodiesel via esterification. For these feedstocks, hydrodeoxygenation is suitable for producing hydrocarbons. However to limit hydrogen consumption, thermal processes are also object of studies. In these thermal processes nickel has been used in the form of supported catalysts but has not been well studied in the form of mixed oxides. This work aims at studying the Ni/Al ratio influence on the properties of unsupported mixed oxides prepared from layered double hydroxides (LDH) precursors, to evaluate their performance in the fast pyrolysis of myristic acid (MA) as a model compound of residual acidic lipids. Prepared materials had molar ratios Ni/Al = 0.3, 1 and 3. The catalysts were obtained through calcination of the precursors, and were characterized by XRD, TGA, FTIR, N-2 adsorption isotherms, TPD of NH3 and EDX analysis. Myristic acid pyrolysis, with catalyst:MA mass ratio of 5:1, was carried out in a micropyrolyzer at 550 degrees C, and the products were analyzed through online GC/MS. Results show that the obtained catalysts presented a rather high surface area, important mesoporosity and NiO and NiAl2O4 crystalline phases. The catalysts with the highest Al content favored cracking with the production of hydrocarbons in the gasoline range, while the sample with highest Ni content favored the production of hydrocarbons in the kerosene range. The catalyst obtained with the combination of Ni/Al = 1 presented the highest surface area and acidity and the lowest NiO crystallite size, resulting in the best MA conversion (similar to 84 %) and deoxygenation degree. It also produced the highest yield in aromatic compounds due to the higher acidity and hydrogen transfer, compared to other catalysts. The present results confirm that catalytic reaction under pyrolysis conditions is able to identify some intrinsic properties of catalysts using model molecules as starting feed.

Perovskite oxides with composition LaNi1-xCoxO3 (x = 0.0; 0.2; 0.5; 1.0) were studied in the chemical looping combustion (CLC) of methane. In situ XRDs under methane flow at different temperatures of LaNi0.5Co0.5O3 and LaNi0.8Co0.2O3 samples, suggest that a different reduction mechanism is activated depending on the composition of the starting material: LaNi0.5Co0.5O3 reduction involved the formation of LaNi0.5Co0.5O2.5 and Co3O4 as intermediate phases, whereas LaNi0.8Co0.2O3 showed an oxygen-deficient perovskite structure as well as spinel and NiO phases. At temperatures higher than 700 ?C, in both samples, the final phases evidenced under methane flow were Ni0, Co0 and La2O3. The substitution of nickel for cobalt contributed to a decrease in the quantity of active oxygen for the methane combustion reaction, making the catalysts less active. However, the insertion of cobalt improved the re-oxidation rate of the catalysts and lead to materials that were less contaminated by coke deposits. During methane CLC, the formation of coke tended to decrease for all samples with the progress of the reaction. After CLC process, the catalysts external morphology was appeared much more uniform. Among the LaNi1-xCoxO3 samples resistant to coke formation (x = 0.5 and 1.0), LaNi0.5Co0.5O3 lead to a complete reduction in less time and is therefore considered the best CLC sample of the series.

One way to take advantage from out-of-specification biodiesel and waste from biodiesel tank bottom drainage is to co-process them in a fluidized catalytic cracking (FCC) unit. The present work deals with the cracking of oleic acid methyl ester (OAME) as a biodiesel model, under conditions close to that of FCC process over ZSM-5 and Y zeolites, either in protonated or sodium forms, towards deoxygenated compounds. Catalytic fast cracking of OAME pre-adsorbed on the catalyst surface was performed, with a catalyst:OAME mass ratio of 10:1 in a micro-pyrolysis system at 650 °C, coupled to a GC/MS for on line analysis of the products. Results show that the cracking of OAME without a catalyst favored the formation of linear alkenes and polyenes. Fast cracking of OAME over HZSM-5 and HY acidic zeolites led to the production of aromatics, due to hydrogen transfer. Cracking over NaY and HY zeolites produced remarkable amounts of ramified saturated hydrocarbons. The formation of alkylated hydrocarbons was not significant over ZSM-5 zeolite probably due to a small pore size of this zeolite. NaY catalyst favored the production of hydrocarbons in the range of kerosene (C8–C12). Low acidic zeolites favored the production of non-aromatic hydrocarbons. Product distribution was affected by catalyst shape selectivity and acidity. These results suggest that residues from the biodiesel chain can be directly co-processed in FCC units to obtain high value hydrocarbons, mainly in the jet fuel and gasoline ranges.

Nos dias de hoje, as microalgas vêm sendo investigadas como fonte de matéria-prima para produzir biocombustíveis devido à sua alta produtividade, ao elevado teor lipídico e à capacidade de crescer em uma grande variedade de climas e de espaços, sem competir com a produção de alimentos. Este trabalho tem como finalidade identificar as patentes referentes à produção de diesel verde a partir de microalgas, empregando catalisadores de nióbio no processo de pirólise. Para isso, foi realizada uma pesquisa nos bancos de dados Espacenet e Instituto Nacional da Propriedade Industrial (INPI), por meio de códigos indexados na Classificação Internacional de Patentes (CIP). Os resultados mostram que não foram encontradas tecnologias usando pirólise rápida e catalisadores de nióbio para transformar os lipídios de microalgas em combustíveis verdes, o que pode justificar a necessidade de um estudo na área.

The aim of this work was to study the cracking of palmitic and oleic acids to reveal the role of alumina surface in the formation of deoxygenated products. Saturated palmitic acid and monounsaturated oleic acid were cracked at 650 degrees C, either in their molecular form or after preadsorption on a transition alumina surface. Cracking was performed in a micro pyrolyser, with fast heating rate, under helium flow and with "on line" products analysis (GC/MS). The alumina played an important role in the products distribution, increasing both the conversion and the deoxygenation efficiency. Oleic acid cracking in the presence of alumina produced a high content of hydrocarbons in the gasoline range (C4-C9), whereas cracking of palmitic acid produced a high content of hydrocarbons both in the kerosene range (C10-C14) and in the gasoline range.

Perovskites with the structural formula La1-xCexNi1-yAlyO3 (x = 0 y = 0; x = 0.05 y = 0; x = 0.05 y = 0.2 and x = 0.05 y = 0.5) were studied in the dry methane reforming in presence of oxygen or Oxy-Dry (OD). The materials were synthetized by the amorphous citrate method and characterized by XRD, in situ XRD under hydrogen and reactional (OD) atmospheres, TPR-H2, XRF, TPSR-OD, TPSR-CH4, TEM, HRTEM and TPO techniques. The catalytic performance was evaluated during 16 h of reaction, with a [CH4/CO2/O2] ratio = 4:2:1, at 800 degrees C and spatial velocity of 210.000 NL.h-1.kgcat- 1. The addition of aluminum and cerium promoted an increase in the catalyst resistance to carbon poisoning, however, the higher the aluminum content was, the lower the reducibility of the perovskites and the nickel particle size. The La0.95Ce0.05Ni0.5Al0.5O3 sample showed the best results, with a maximum CH4 and CO2 conversion of 85 % and 86 % respectively and the higher syngas yield (45 % for CO and 48 % for H2). This sample presented the lowest Ni degrees particle size and carbon deposition after 16 h time on stream. No sign of deactivation was found for all the studied catalysts, showing the superior properties of catalysts prepared through perovskite-like mixed oxides.

Microalgas como matéria prima para a produção de compostos lipídicos precursores de combustíveis verdesMicroalgae as raw materials for the production of lipid compounds

Em diferentes instâncias "13 Reasons Why" desdobra em diálogos de extrema importância, principalmente na Educação Sexual do sujeito adolescente.Este estudo dispõe o questionamento em como a série demonstra o abuso sexual, visualizando de forma indireta uma possível omissão escolar, bem como os transtornos ocasionados por tal ato e o distanciamento da abordagem pedagógica da escola em relação à Educação Sexual.O presente artigo traz como objetivo um estudo que busca analisar qual o olhar referente ao abuso sexual e possíveis transtornos no enredo escolar por meio de imagens e diálogos demonstramos na série, bem como a omissão escolar frente à